The present invention relates to a connection for the sections of a separable, i.e. multi-section, guide tube and of a drive shaft disposed therein, especially a connection for the tool of a manually guided free-cutting device, whereby the tube sections are axially interconnected, and the shaft sections are interlockingly coupled together, with the ends of the shaft sections interengaging one another.
The guide tube, and the drive shaft disposed therein, are separable to facilitate transport of, in particular, a manually guided free-cutting device. In this connection, the guide tube serves for guiding the tool, which is adapted to be driven by the drive shaft. The drive shaft is connected to a drive motor, which is disposed on that side of the guide tube opposite from the tool. A free-cutting device of this general type is know from U.S. Pat. No. 4,122,601. In this device, the tube sections of the guide tube are plug connected together, whereby the end of one of the tube sections carries the coupling sleeve into which extends a coupling element that is fixed at the end of the other tube section. The detachable plug connection can be secured by clamping elements. The shaft sections are coupled together in order to transmit the torque. With the known free-cutting device, on the one hand the transmission of force is proposed by a free running roller clutch, whereby the end of one of the shaft sections projects into a coupling drum secured to the end of the other shaft section, and the force transmission is effected in a frictionally engaging manner by means of the clutch rollers that rotate between the respective outer surfaces. Unfortunately, the assembly of this known connection is extremely complicated, and it has been repeatedly demonstrated that during connection of the sections of the guide tube, the shaft sections that remain non visible in the tube do not properly cooperate with one another. Furthermore, this known patent discloses a connection of the shaft sections by means of a dog clutch or coupling. The clutch parts that belong together, and which are respectively secured to the adjacent ends of the shaft sections that are to be connected, interlockingly couple and interengage in a specific angular rotational position. However, during assembly of the guide tube/drive shaft the clutch halves are normally not disposed in the required angular rotational position relative to one another, so that one of the shaft sections must be rotated into the proper position, which is expediently done by a second person. Here also the assembly of the free-cutting device is extremely complicated and time consuming, since more or less a number of tries to obtain the angular rotational positioning of the clutch parts are necessary and often during the connection of the parts of the guide tube the positive and interlocking connection between the drive shaft sections does not result.
It is therefore an object of the present invention to improve the connection of the aforementioned general type in such a way that a simple and reliable assembly of the guide tube and of the drive shaft is possible.